Gas turbine engines often include so-called "start" injectors that are used when initiating operation of the turbine. In relatively small turbine engines in airborne environments, fuel flows at high altitudes during starting are frequently quite low. Consequently, with conventional start injectors, high fuel pressures are required to achieve pressure atomization of the fuel, particularly since air blast atomization is not a viable alternative during start up when the turbine is rotating at a minor per cent of its rated speed. At the same time, at such low speeds, it is difficult with available fuel pumps to generate the necessary fuel pressure.
To meet these difficulties, conventional start injectors have extremely small orifices to provide the desired atomization making them precision formed parts. They are thus costly to manufacture. At the same time, because of the very small orifices employed, they are prone to plugging, a factor that clearly detracts from reliability. In addition, the effects of the relatively small scale of these engines and their components reduce fuel atomization effectiveness.
The present invention is directed to overcoming one or more of the above problems.